20604721481 has 2 divisors, whose sum is σ = 20604721482. Its totient is φ = 20604721480.

The previous prime is 20604721471. The next prime is 20604721549. The reversal of 20604721481 is 18412740602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20589667081 + 15054400 = 143491^2 + 3880^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20604721481 is a prime.

It is a super-2 number, since 2×20604721481² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20604721451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10302360740 + 10302360741.

It is an arithmetic number, because the mean of its divisors is an integer number (10302360741).

Almost surely, 2^20604721481 is an apocalyptic number.

It is an amenable number.

20604721481 is a deficient number, since it is larger than the sum of its proper divisors (1).

20604721481 is an equidigital number, since it uses as much as digits as its factorization.

20604721481 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21504, while the sum is 35.

The spelling of 20604721481 in words is "twenty billion, six hundred four million, seven hundred twenty-one thousand, four hundred eighty-one".